# plot an eight variable function

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shirin mhd on 26 Aug 2022
Commented: shirin mhd on 27 Aug 2022
Hi everyone
I have an equation with 8 variables. I know how to plot a 3-variable equation in Matlab, but I need to plot this function with eight variables.
y= (5)*x(1)^2-(200)*x(1)+...
(0.3)*x(2)^2-(150)*x(2)+...
(0.4)*x(3)^2- (50)*x(3)+...
(2)*x(4)^2 - (82)*x(4)+...
(3)*x(5)^2 -(250)*x(5)+...
(5)*x(6)^2 - (23)*x(6)+...
(4)*x(7)^2 -(201)*x(7)+...
(12)*x(8)^2-(300)*x(8);
I really appreciate any help.
shirin mhd on 27 Aug 2022
yeah, that was my fault, thank for your attention.

John D'Errico on 26 Aug 2022
Edited: John D'Errico on 26 Aug 2022
It is easy, even trivial to do. All you need is one of those nice hyper-dimensional monitors. They are difficult to buy though, as you can only obtain them from Starfleet Command, and shipping is always really slow from the future. It might take centuries to get one, in fact. I do hear that the Borg will deliver though, but do you really want the Borg to show up on your doorstep? (Well, maybe if it was Jeri Ryan ... No, Not even then.)
Seriously, you can't do it. What is a plot? A plot is a TWO dimensional thing, viewed on your monitor. Yes, you can see three dimensional stuff, but even then, you really need to rotate the view around to understand it as a 3-d thing. A picture is just a projection of that thing, rendered into only TWO dimensions. Otherwise, without the cues to understand what the thing is in 3-d, your brain cannot percieve what it sees. So without the extra visual cues, you end up with the same confusions as if you were looking at an MC Escher print.
But now, how do you intend to view that 8-dimensional monster? Again, we will assume your hyper-dimensional monitor is out of stock, or perhaps just forward-ordered. Perhspa you can look at a picture of a 4 or 6 dimensional hypercube, and understand what you are looking at. If you can, then you are smarter than 99.999% of all people.
Remember your brain understands 3-d. With some help, it can handle a 2-d image, and recognize what it sees as 3-d. With some extra mechanisms, like 3-d glasses, so each eye can now get a subtly different image, you can even "see" in 3-d then. But that is the limit.
Your brain is just not built to handle 8-d.
shirin mhd on 27 Aug 2022
Thank you very much for your very detailed explanation.